Enquiry Question 1 Flashcards
Why are ice cores Important
Bubbles trapped in the ice contain co2 from the atmosphere, these show low concentrations in glacial periods and high concentrations in interglacial periods
Describe the quaternary period
Broken down into two periods
Holocene and Pleistocene
What is the milankovitch cycle
Eccentricity of orbit
Changes from elliptical to a more circular orbit and back
Approximately 100,000
What is axial tilt
This varies from 21.8° to 24.4°
This happens over a 41,000year time scale
This impacts on the intensity of light that is received at the poles and therefore I file see the Sean’s on earth
Wobble / the precession of the earth
This is known as the precession of the earth
Wobbles on its axis changing the point in time the earth is nearest the sun
Over a 21,000 year cycle
This causes long term changes to when different seasons occur along the earths orbit path
How do the three cycles work together
The three cycles can come together to Mina,it’s the amount of solar energy reaching the northern hemisphere during the summer
The milankovitch theory Is supported by evidence of glacial periods occurring approximately 100,000 years
What does it take to form a glacial period to form
For fast amounts of ice to form a temperature change of 5° is needed
The milankovitch cycle may trigger change but is is feedback mechanisms which that magnify them and lead us into or out of glacial periods
Describe a positive feedback mechanism
1- small increase to snow and ice cover can raise surface albedo
2- more solar radiation is reflected of ice to space
3- temperatures get colder more ice forms leads to more ice cover
Describe negative feedback mechanisms
1- increases global warming and industry leads to more evaporation which increases cloud cover
2- increased cloud cover reflects solar energy back into space
3- reduces the intensity of global warming
What are the short term fluctuations
There are other factors which can cause climate change
-solar forcing
-volcanic causes
How does solar forcing cause climate change
Energy emitted from the sun varies due to sunspots, which cycle every 11 years
Solar forcing is seen as attributing 20% of warming in the 20th century
How do volcanoes contribute to climate change
Highly explosive volcanoes eject huge amounts of ash, sulfer dioxide , CO2, and water Vapour into the atmosphere
These particles spread around the globe blocking out sunlight
This causes a temp drop temporarily
What was the little ice age
Between 1550-1750 there was a trough in cold temperatures they may have caused
- abandonment of hill farms in Northern Europe
-glaciers advance down valleys
-arctic sea ice spread further south with polar bears found in Iceland
-rivers froze in UK, lowland Europe and New York
-curling developed as a sport in Scotland
Why do the little ice age not develop into a stadial
Due to impacts of the industrial revolution creating a warming effect
What are the 4 types of glaciers
Warm based
Cold based
Polythermal
Surging
Describe warm based/temperate glaciers
They occur at high altitudes outside of polar regions
Temperatures fluctuate on surface
Temperatures below surface are close to melting point because of the pressure building up
Having liquid at the base causes the glacier to melt continually ( basal ice )
The ice also has lots of debris at the bottom this creates many subglacial deposits and landforms
